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This chapter contains information on enabling, shutting down, and displaying messages pertinent to interface configuration and operation. Also discussed in this chapter are the procedures and command descriptions for configuring and maintaining the following interface components of the router:
You will also find information about configuring the serial Dial Backup feature, and how to configure a null interface and the Point-to-Point Protocol (PPP) in this chapter.
To enable an interface, you must be in the configuration command collection mode. To enter this mode, type the EXEC command configure at the EXEC prompt; the configure command will place the system into the configuration command collection mode. Once in the command collection mode, start configuring the interface by entering the interface command. Once an interface is configured, you can check its status by entering EXEC show commands at the EXEC prompt.
This chapter provides software configuration information only. For hardware technical descriptions, and for information about installing these interfaces, refer to the appropriate Cisco Hardware Installation and Reference publication.
Summaries of the interface configuration commands and EXEC monitoring commands described in this chapter are included at the end of the chapter.
Enter the interface global configuration command in configuration mode to identify a specific network interface (for example, a serial port, Ethernet port, or a Token Ring port). By entering this command you begin the configuration subcommand collection mode for the specified interface.
The interface command has the following syntax:
interface type unitThe argument type identifies the interface type; the argument unit identifies the connector or interface card number. Unit numbers are assigned at the factory at the time of installation, or when added to a system, and can be displayed with the show interfaces command.
This example begins interface configuration subcommand collection mode for serial connector 0 (interface serial 0).
interface serial 0
Use the EXEC command show interfaces (described later in this chapter), to determine the interface type and unit numbers.
In the interface configuration subcommand collection mode, you enter the interface subcommands for your particular routing or bridging protocol. The interface configuration subcommand collection mode ends when you enter a command that is not an interface subcommand, or when you type the Ctrl-Z sequence.
To add a descriptive name to an interface, use the description interface subcommand.
description name-stringThe argument name-string is descriptive text to help you remember what is attached to this interface. The description command is meant solely as a comment to be put in the configuration to help you remember what certain interfaces are for. The description will appear in the output of the following commands: show configuration, write terminal, and show interfaces. The no version removes the name-string.
This example describes a 3174 controller on serial 0.
interface serial 0 description 3174 Controller for test lab
You disable an interface using the shutdown interface subcommand. The full syntax for this command follows:
shutdownThe shutdown command disables all functions on the specified interface, as well as prevents the transmission of all the packets. The command also marks the interface as unavailable, which is communicated to other network servers through all dynamic routing protocols. The interface will not be mentioned in any routing updates. On serial interfaces, this command causes the DTR signal to be dropped. On FDDI interfaces, this command causes the optical bypass switch, if present, to go into bypass mode. On Token Ring interfaces, this command causes the interface to de-insert from the ring.
To restart a disabled interface, use the no shutdown interface subcommand.
To check whether an interface is disabled, use the EXEC command show interfaces as described in the next section. An interface that has been shut down is shown as administratively down in the display from this command.
This example turns off the interface Ethernet 0:
interface ethernet 0 shutdown
This example turns the interface back on:
interface ethernet 0 no shutdown
To clear the interface counters shown with the show interfaces command, enter the following command at the EXEC prompt:
clear counters [interface-name]The command clears all the current interface counters from the interface unless the optional arguments type and unit are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on) from a specific unit or card number.
The Cisco software contains commands that you can enter at the EXEC prompt to display different information about the interface including the version of the software and the hardware, the controller status, and some statistics about the different interfaces. These commands begin with the word "show." (The full list of these commands can be displayed by entering the command show ? at the EXEC prompt.) A description of interface-specific show commands follow.
The show version command displays the configuration of the system hardware, the software version, the names and sources of configuration files, and the boot images. Enter this command at the EXEC prompt:
show versionThe following shows sample output from this command:
GS Software, Version 9.0(1) Copyright (c) 1986-1992 by cisco Systems, Inc. Compiled Fri 14-Feb-92 12:37 System Bootstrap, Version 4.3 thor uptime is 2 days, 10 hours, 0 minutes System restarted by reload System image file is unknown, booted via tftp from 131.108.13.111 Host configuration file is "thor-boots", booted via tftp from 131.108.13.111 Network configuration file is "network-confg", booted via tftp from 131.108.13.111 CSC3 (68020) processor with 4096K bytes of memory. X.25 software. Bridging software. 1 MCI controller (2 Ethernet, 2 Serial). 2 Ethernet/IEEE 802.3 interface. 2 Serial network interface. 32K bytes of non-volatile configuration memory. Configuration register is 0x0
In the output, the first line is the bootstrap version string. The second through fourth lines list information about the system software; the version number is on the second line. Always specify the complete version number when reporting a possible software problem. In the sample output, the version number is 9.0, initial release.
The fifth line shows the system name and uptime, or the amount of time the system has been up and running. The sixth line provides a log of how the system was last booted, both as a result of normal system startup and of system error. For example, this line may be displayed to indicate a bus error that is generally the result of an attempt to access a nonexistent address:
System restarted by bus error at PC0XC4CA address 0X210C0C0
If the software was booted over the network, the seventh line shows the Internet address of the boot host. If the software was loaded from onboard ROM, this line reads running default software. The eighth and ninth lines identify the names and sources of the host and network configuration files.
The remaining lines of output show the hardware configuration and any non-standard software options. The configuration register contents are displayed in hexadecimal notation.
The show controllers command displays current internal status information for different interface cards. Enter this command at the EXEC prompt:
show controllers {serial|token|mci|cbus|fddi}Use the following keywords to display the information about that card:
Sample output for the MCI controller card follows. Table 1-1 describes the fields seen.
MCI 0, controller type 1.1, microcode version 1.8
128 Kbytes of main memory, 4 Kbytes cache memory
22 system TX buffers, largest buffer size 1520
Restarts: 0 line down, 0 hung output, 0 controller error
Interface 0 is Ethernet0, station address 0000.0c00.d4a6
15 total RX buffers, 11 buffer TX queue limit, buffer size 1520
Transmitter delay is 0 microseconds
Interface 1 is Serial0, electrical interface is V.35 DTE
15 total RX buffers, 11 buffer TX queue limit, buffer size 1520
Transmitter delay is 0 microseconds
High speed synchronous serial interface
Interface 2 is Ethernet1, station address aa00.0400.3be4
15 total RX buffers, 11 buffer TX queue limit, buffer size 1520
Transmitter delay is 0 microseconds
Interface 3 is Serial1, electrical interface is V.35 DCE
15 total RX buffers, 11 buffer TX queue limit, buffer size 1520
Transmitter delay is 0 microseconds
High speed synchronous serial interface
| Field | Description |
|---|---|
| Card type and number | Unit type and number card (varies depending on card) |
| controller type | Version number of the card |
| microcode version | Version number of the card's internal software (in read-only memory) |
| main memory cache memory | Amount of main and cache memory on the card |
| system TX | Number of buffers that hold packets to be transmitted buffers |
| Restarts line down hung output controller error | Count of restarts due to the following conditions: Communication line down Output unable to transmit Internal error |
| interface..is | Names of interfaces, by number |
| electrical interface | Line interface type for serial connections |
| RX buffers | Number of buffers for received packets |
| TX queue limit | Maximum number of buffers in transmit queue |
| Transmitter delay | Delay between outgoing frames |
| Station address | The hardware address of the interface |
The Cisco software also provides the show interfaces command, which displays statistics for the network interfaces on the network server. Enter this command at the EXEC prompt:
show interfaces [type unit]Specify the optional arguments type and unit to display statistics for a particular network interface. The argument type can be one of the following: ethernet, serial, tokenring, fddi, hssi, or ultranet. Use the argument unit to specify the interface unit number.
You will use the show interfaces command frequently while configuring and monitoring your modules.
For further explanations and examples about a specific interface, refer to the following sections in this chapter: "Monitoring the Serial Interface," "Monitoring the Ethernet Interface," "Monitoring the Token Ring Interface," "Monitoring the FDDI," "Monitoring the HSSI," and "Monitoring the UltraNet Interface."
Support for the serial interface is supplied on one of Cisco Systems' serial network interface cards:
The high-speed synchronous serial interface is also supported on the IGS network server.
To specify a serial interface, use this configuration command:
interface serial unitSpecify the serial interface connector number with the argument unit.
Follow this command with the routing or bridging interface subcommands for your particular protocol or application, as described later in this manual.
The SCI and MCI cards can query the appliques to determine their types. However, they do so only at system startup, so the appliques must be attached when the system is started. Issue a show controllers serial or show controllers mci command to determine how the serial card has identified them. The command will also show the capabilities of the serial card and report controller-related failures.
This command begins configuration on interface serial 0.
interface serial 0
The serial interfaces support the following kinds of serial encapsulations:
With the exception of the PPP and HDLC encapsulations, these serial encapsulation methods are described in the chapter "Configuring Packet-Switched Software." The HDLC serial encapsulation method is described in this section. PPP serial encapsulation is described later in this chapter, in "Configuring the Point-to-Point Protocol."
Change the encapsulation method by using the interface configuration subcommand encapsulation followed by a keyword that defines the encapsulation method.
encapsulation encapsulation-typeThe encapsulation-type argument is a keyword that identifies one of the following serial encapsulation types that Cisco Systems' software supports:
Cisco provides HDLC serial encapsulation for serial lines. This encapsulation method provides the synchronous framing and error detection functions of HDLC without windowing or retransmission. Although HDLC is the default serial encapsulation method, it can be reinstalled using the hdlc keyword with the encapsulation command as follows:
encapsulation hdlcUse the command clear interface to reset the hardware logic on an interface. Enter this command at the EXEC prompt:
clear interface interface-nameThe arguments type and unit specify a particular interface type and its unit number. In this case, the argument type is serial.
In general, use the command show interfaces to display information about the serial interface. Enter this command at the EXEC prompt:
show interfaces serial [type unit]The argument type is specified as serial and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command for an HDLC synchronous serial interface is provided below. Table 1-2 describes the fields seen.
Serial 0 is up, line protocol is up
Hardware is MCI Serial
Internet address is 150.136.190.203, subnet mask is 255.255.255.0
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 0:00:07, output 0:00:00, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 0 bits/sec, 0 packets/sec
16263 packets input, 1347238 bytes, 0 no buffer
Received 13983 broadcasts, 0 runts, 0 giants
2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort
22146 packets output, 2383680 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets, 0 restarts
1 carrier transitions
| Field | Description |
|---|---|
| Serial ... is {up |down} ...is administratively down | Tells whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. |
| line protocol is {up | down | administratively down} | Tells whether the software processes that handle the line protocol think the line is usable (are keepalives successful?). |
| Hardware is | Specifies the hardware type. |
| Internet address is | Specifies the Internet address and subnet mask, followed by packet size. |
| MTU | Maximum Transmission Unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. |
| Encapsulation | Encapsulation method assigned to interface. |
| loopback | Tells whether loopback is set or not. |
| keepalive | Tells whether keepalives are set or not. |
| Last input | The number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| output hang | The number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
| Output queue, Input Queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
| Five minute input rate Five minute output rate | The average number of bits and packets transmitted per second in the last five minutes. |
| packets input | The total number of error-free packets received by the system. |
| broadcasts | The total number of broadcast or multicast packets received by the interface. |
| runts | The number of packets that are discarded because they are smaller than the medium's minimum packet size. |
| giants | The number of packets that are discarded because they exceed the medium's maximum packet size. |
| input error | The total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum may not balance with the other counts. |
| CRC | The Cyclic Redundancy Checksum generated by the originating station or far-end device does not match the checksum calculated from the data received. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link. |
| frame | The number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems. |
| overrun | The number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. Broadcast storms and bursts of noise can cause the ignored count to be increased. |
| abort | An illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment. |
| packets output | Total number of messages transmitted by the system. |
| bytes output | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces. |
| output errors | The sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
| collisions | Number of messages retransmitted due to an Ethernet collision. This usually is the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). A packet that collides is counted only once in output packets. |
| interface resets | The number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds' time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down. |
| restarts | The number of times the controller was restarted because of errors. |
| carrier transitions | The number of times the carrier detect signal of a serial interface has changed state. Indicates modem or line problems if the carrier detect line is changing state often. |
Use the commands debug serial-interface and debug serial-packet to debug serial interface events. The EXEC commands are as follows:
debug serial-interface debug serial-packetUse debug serial-packet for detailed debugging information, and debug serial-interface for more general information.
Use the undebug serial-interface and undebug serial-packets to turn off messaging from these debug commands.
Support for the Ethernet interface is supplied on one of Cisco Systems' Ethernet network interface cards:
The Ethernet interface is also supported on the IGS network server.
To specify an Ethernet interface, use this configuration command:
interface ethernet unitSpecify the Ethernet interface connector number with the argument unit.
Follow this command with the routing or bridging interface subcommands for your particular protocol or application as described later in this manual.
This command begins configuration on interface Ethernet 1.
interface ethernet 1
The Ethernet interface supports a number of encapsulation methods. These methods are assigned by using the interface subcommand encapsulation followed by a keyword that defines the encapsulation method. The particular encapsulation method used depends on the protocol. Currently, there are three common Ethernet encapsulation methods:
The syntax of the encapsulation command follows:
encapsulation encapsulation-typeThe encapsulation-type is one of the following three keywords:
These commands enable standard Ethernet Version 2.0 encapsulation on interface Ethernet 0.
interface ethernet 0 encapsulation arpa
Use the command clear interface to reset the hardware logic on an interface. Enter this command at the EXEC prompt:
clear interface interface-nameThe arguments type and unit specify a particular interface type and its unit number. In this case, the argument type is ethernet.
Use the command show interfaces to display information about the Ethernet interface. Enter this command at the EXEC prompt:
show interfaces [type unit]Where type is the ethernet keyword and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command is provided on the following page. Table 1-3 describes the fields seen.
Ethernet 0 is up, line protocol is up
Hardware is MCI Ethernet, address is aa00.0400.0134 (bia 0000.0c00.4369)
Internet address is 131.108.1.1, subnet mask is 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
ARP type: ARPA, PROBE, ARP Timeout 4:00:00
Last input 0:00:00, output 0:00:00, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 2 drops
Five minute input rate 61000 bits/sec, 4 packets/sec
Five minute output rate 1000 bits/sec, 2 packets/sec
2295197 packets input, 305539992 bytes, 0 no buffer
Received 1925500 broadcasts, 0 runts, 0 giants
3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
3594664 packets output, 436549843 bytes, 0 underruns
8 output errors, 1790 collisions, 10 interface resets, 0 restarts
| Field | Description |
|---|---|
| Ethernet ... is up ...is administratively down | Tells whether the interface hardware is currently active and if it has been taken down by an administrator. |
| line protocol is {up | down | administratively down} | Tells whether the software processes that handle the line protocol believe the interface is usable (are keepalives successful?). |
| Hardware | Specifies the hardware type (for example, MCI Ethernet, SCI, cBus Ethernet) and address. |
| Internet address | Lists the Internet address followed by subnet mask and then the packet size. |
| MTU | Maximum Transmission Unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. |
| Encapsulation | Encapsulation method assigned to interface. |
| ARP type: | Type of Address Resolution Protocol assigned. |
| loopback | Tells whether loopback is set or not. |
| keepalive | Tells whether keepalives are set or not. |
| Last input | The number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| output | Number of hours, minutes, and seconds since the last packet was successfully transmitted by the interface. Useful for knowing when a dead interface failed. |
| output hang | The number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
| Last clearing | The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared. |
| Output queue, Input Queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
| Five minute input rate, Five minute output rate | The average number of bits and packets transmitted per second in the last five minutes. |
| packets input | The total number of error-free packets received by the system. |
| Received ... broadcasts | The total number of broadcast or multicast packets received by the interface. |
| runts | The number of packets that are discarded because they are smaller than the medium's minimum packet size. For instance, any Ethernet packet that is less than 64 bytes is considered a runt. |
| giants | The number of packets that are discarded because they exceed the medium's maximum packet size. For example, any Ethernet packet that is greater than 1,518 bytes is considered a giant. |
| input error | Includes runts, giants, no buffer, CRC, frame, overrun, and ignored counts. Other input-related errors can also cause the input errors count to be increased, and some datagrams may have more than one error; therefore, this sum may not balance with the sum of enumerated input error counts. |
| CRC | The Cyclic Redundancy Checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. |
| frame | The number of packets received incorrectly having a CRC error and a noninteger number of octets. On a LAN, this is usually the result of collisions or a malfunctioning Ethernet device. |
| overrun | The number of times the receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased. |
| packets output | Total number of messages transmitted by the system. |
| bytes | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces. |
| output errors | The sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
| collisions | The number of messages retransmitted due to an Ethernet collision. This is usually the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). A packet that collides is counted only once in output packets. |
| interface resets | The number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds' time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down. |
| restarts | The number of times a Type 2 Ethernet controller was restarted because of errors. |
Use the command debug broadcast to debug MAC broadcast packets. Enter this command at the EXEC prompt:
debug broadcastUse the undebug broadcast command to turn off messaging.
Use the command debug packet to enable a log of packets that the network is unable to classify. Examples of this are packets with unknown link type, or IP packets with an unrecognized protocol field. Enter this command at the EXEC prompt.
debug packetUse the undebug packet command to turn off messaging.
Support for the Token Ring interface is supplied on one of Cisco Systems' Token Ring network interface cards:
The Cisco Token Ring interface supports both routing (Level 3 switching) and source-route bridging (Level 2 switching). The use of routing and bridging is on a per-protocol basis. For example, IP traffic could be routed while SNA traffic is bridged. The routing support interacts correctly with source-route bridges.
To configure a Token Ring interface, use this configuration command:
interface tokenring unitSpecify the card number with the argument unit.
Follow this command with the bridging interface subcommands for your particular protocol or applications as described later in this manual.
This command begins configuration on the first Token Ring interface.
interface tokenring 0
The Token Ring interface on the IGS/TR can run at either 4 or 16 Mbps. This speed is software selectable. The IGS/TR does not default to any particular ring speed. This speed must be provided the first time the IGS/TR is put to use.
 | Caution Configuring a ring speed that is wrong or incompatible with the connected Token Ring will cause the ring to beacon, which effectively takes the ring down and makes it nonoperational. |
Use the ring-speed interface subcommand to set ring speed for an IGS/TR Token Ring interface. The command syntax is:
ring-speed speedThe argument speed can be either 4 or 16. When specified as 4, ring speed is set for 4 Mbps operation; when specified to 16, ring speed is set for 16 Mbps operation. The default is 16.
The following commands set an IGS/TR Token Ring interface ring speed to 4 Mbps.
interface tokenring 0 ring-speed 4
The CSC-R16 (or CSC-R16M), CSC-2R, and CSC-1R cards all support early token release, a method whereby these interfaces can release the token back onto the ring immediately after transmitting, rather than waiting for the frame to return. This can help to increase the total bandwidth of the Token Ring. The following interface subcommands control the use of this feature:
early-token-releaseBy default, early token release is not enabled on the interface. The no early-token-release command disables this feature.
For example, to enable the use of early token release on your tokenring 1 interface, issue the following configuration commands:
interface tokenring 1 early-token-release
Cisco's Token Ring interface by default uses the SNAP encapsulation format defined in RFC 1042. It is not necessary to define an encapsulation method for this interface.
Use the command clear interface to reset the hardware logic on an interface. Enter this command at the EXEC prompt:
clear interface interface-nameThe arguments type and unit specify a particular interface type and its unit number. In this case, the argument type is tokenring.
Use the command show interfaces to display information about the Token Ring interface and the state of source route bridging. Enter this command at the EXEC prompt:
show interfaces [type unit]The argument type is the keyword tokenring and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces. Sample output of this command is provided below. Table 1-4 describes the fields seen.
TokenRing 0 is up, line protocol is up
Hardware is 16/4 Token Ring, address is 5500.2000.dc27 (bia 0000.3000.072b)
Internet address is 150.136.230.203, subnet mask is 255.255.255.0
MTU 8136 bytes, BW 16000 Kbit, DLY 630 usec, rely 255/255, load 1/255
Encapsulation SNAP, loopback not set, keepalive set (10 sec)
ARP type: SNAP, ARP Timeout 4:00:00
Ring speed: 16 Mbps
Single ring node, Source Route Bridge capable
Group Address: 0x00000000, Functional Address: 0x60840000
Last input 0:00:01, output 0:00:01, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 0 bits/sec, 0 packets/sec
16339 packets input, 1496515 bytes, 0 no buffer
Received 9895 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
32648 packets output, 9738303 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets, 0 restarts
5 transitions
| Field | Description |
|---|---|
| Token Ring is up | down | The interface is currently active and inserted into ring (up) or inactive and not inserted (down). |
| Token Ring is Reset | Hardware error has occurred. |
| Token Ring is Initializing | Hardware is up, in the process of inserting the ring. |
| Token Ring is Administratively Down | Hardware has been taken down by an administrator. |
| line protocol is {up | down | administratively down} | Tells whether the software processes that handle the line protocol believe the interface is usable (are keepalives successful?). |
| Hardware | Specifies the hardware type (Token Ring or 16/4 Token Ring) and provides the address. |
| Internet address | Lists the Internet address followed by subnet mask. |
| MTU | Maximum Transmission Unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. |
| Encapsulation | Encapsulation method assigned to interface. |
| loopback | Tells whether loopback is set or not. |
| keepalive | Tells whether keepalives are set or not. |
| ARP type: | Type of Address Resolution Protocol assigned. |
| Ring speed: | Speed of Token Ring--4 or 16 Mbps. |
| {Single ring | multiring node} | Indicates whether a node is enabled to collect and use source routing information (RIF) for routable Token Ring protocols. |
| Group Address: | The interface's group address, if any. The group address is a multicast address; any number of interfaces on the ring may share the same group address. Each interface may have at most one group address. |
| Last input | The number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| output hang | The number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
| Output queue, Input Queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
| Five minute input rate, Five minute output rate | The average number of bits and packets transmitted per second in the last five minutes. |
| packets input | The total number of error-free packets received by the system. |
| broadcasts | The total number of broadcast or multicast packets received by the interface. |
| runts | The number of packets that are discarded because they are smaller than the medium's minimum packet size. |
| giants | The number of packets that are discarded because they exceed the medium's maximum packet size. |
| CRC | The Cyclic Redundancy Checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of a station transmitting bad data. |
| frame | The number of packets received incorrectly having a CRC error and a noninteger number of octets. |
| overrun | The number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased. |
| packets output | Total number of messages transmitted by the system. |
| bytes output | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never be reported on some interfaces. |
| output errors | The sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
| collisions | Since a Token Ring cannot have collisions, this statistic is nonzero only if an unusual event occurred when frames were being queued or dequeued by the system software. |
| interface resets | The number of times an interface has been reset. The interface may be reset by the administrator or automatically when an internal error occurs. |
| Restarts | Should always be zero for Token Ring interfaces. |
| transitions | The number of times the ring made a transition from up to down, or vice versa. A large number of transitions indicates a problem with the ring or the interface. |
Use the EXEC command debug token-ring to display messages about the Token Ring interface activity. This command reports several lines of information for each packet sent or received and is intended for low traffic, detailed debugging.
debug token-ringThe Token Ring interface records detailed information regarding the current state of the ring. These messages are only displayed when debug token-events is enabled.
Enter the undebug token-ring and undebug token-event commands to turn off the messages.
The last ring status message is displayed in the EXEC command show interfaces display for a Token Ring interface. Table 1-5 describes the messages displayed by this command.
| Message | Description |
|---|---|
| Signal Loss | The controller detected loss of signal on the interface. Several situations can cause this to happen, but the most likely is that another station has just inserted, causing a disruption in service that is reported as signal loss. |
| Hard Error | This error indicates a significant problem that is preventing transmission of data. There may be a break in the physical cabling or an inserted interface may have died. This message is displayed when the interface is either transmitting or receiving beacon frames. |
| Soft Error | The interface has detected an aberration on the ring and is transmitting a Report Error MAC frame. These frames are used to report the following types of errors: · Line Error (code violation, token code violation, CRC violation) · Burst Error · MAC AC Set Error · Lost Frame Error · Frame Copied · Receiver Congestion · Token Error These errors are described more fully in the IEEE 802.5 standard. |
| Ring Beacon | The interface is transmitting beacon frames onto the ring. Something is wrong with the ring. |
| Wire Fault | The interface has detected an open or short circuit in the lobe data path. The data path starts at the edge of the chipset, and includes the Token Ring transition cable and any other cabling connection on the Multistation Access Unit. |
| HW Removal | The interface has detected an internal hardware error and has removed itself from the ring. |
| Remote Removal | The interface received a Remove Ring Station MAC frame from another station on the ring. The interface has removed itself from the ring. |
| Counter Overflow | Indicates an internal counter is close to reaching its maximum value. The Token Ring monitor firmware automatically reads and clears this condition. |
| Only Station | The interface has detected that it is the only interface connected and inserted on the ring. |
| Ring Recovery | The interface is either transmitting or receiving Claim Token MAC frames. This condition is cleared when an Active Monitor has been determined and it transmits a Ring Purge MAC frame. |
FDDI is an ANSI-defined standard for timed 100-Mbps token-passing over fiber-optic cable. Support for the Fiber Distributed Data Interface (FDDI) is supplied on Cisco Systems' FDDI interface (CSC-FCI) card. Cisco's implementation of FDDI complies with Version 6.1 of the X3T9.5 FDDI specification, offering a Class A dual-attach interface that supports the fault-recovery methods of the Dual-Attach Stations (DASs).
An FDDI network consists of two counter token-passing fiber-optic rings. On most networks, the primary ring is used for data communication and the secondary ring is used as a hot standby. The FDDI standard sets a 200 kilometers total fiber length for multimode fiber, and 10 kilometers for single-mode fiber, both of which are supported by Cisco's FDDI interface controller. (The maximum circumference of the FDDI network is only half the specified kilometers because of the wrapping, or the looping back of the signal, that occurs during fault isolation.) The FDDI standard allows a maximum of 500 stations with a maximum distance between active stations of two kilometers. The FDDI frame can contain a minimum of 76 bytes and a maximum of 4500 bytes.
Cisco also provides support for some of the FDDI MIB variables as described in RFC 1285, "FDDI Management Information Base," January 1992 by Jeffrey D. Case of the University of Tennessee and SNMP Research, Inc. One such variable that Cisco supports is snmpFddiSMTCFState.
To specify an FDDI, use the following configuration command:
interface fddi unitSpecify the interface number with the argument unit.
Follow this command with the routing or bridging interface subcommands for your particular protocol or application as described later in this manual.
Cisco's FDDI interface by default uses the SNAP encapsulation format defined in RFC 1042. It is not necessary to define an encapsulation method for this interface.
The EXEC command show interfaces displays information about the FDDI interface, and its use is recommended when configuring the interface.
What follows is a sample of a partial display of FDDI-specific data from the show interfaces command output. Table 1-6 describes the fields displayed.
Fddi 0 is up, line protocol is up
Hardware type is cBus Fddi, hardware address is AA00.0400.6510
Internet address is 131.111.21.6, subnet mask is 255.255.255.0
MTU 4470 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation is SNAP, loopback is not set, keepalive is not set (10 sec.)
ARP type: SNAP
Phy-A state is active, neighbor is B, cmt signal bits 08/20C, status ALS
Brk 1, Con 1, Tra 0, Nxt 11, Sig 10, Join 1, Vfy 1, Act 1
Phy-B state is active, neighbor is A, cmt signal bits 20C/08, status ILS
Brk 1, Con 1, Tra 0, Nxt 11, Sig 10, Join 1, Vfy 1, Act 1
CFM is wrap A, token rotation 5000 usec, ring operational 0:01:42
Upstream neighbor 0800.2008.C52E, downstream neighbor 0800.2008.C52E
Last input 0:00:24, output 0:00:15, output hang never
Output queue 0/25, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 1 bits/sec, 0 packets/sec
2725 packets input, 166225 bytes, 0 no buffer
Received 2725 broadcasts, 0 runts, 0 giants
2 input errors, 2 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
5184 packets output, 316224 bytes
0 output errors, 0 collisions, 1 interface resets, 0 restarts
4 transitions
The received CMT bits are sometimes helpful if the Cisco network server is having problems establishing a connection to the remote Physical connection.
In the previous display, Physical A (Phy-A) has completed CMT with its neighbor. The state is active and the display indicates a Physical B type neighbor. The neighbor is determined from the received signal bits, as follows:
The received value equals 0x20C. Bit positions 1 and 2 (0 1) indicate a Physical B type connection.
The transition states displayed indicate that the CMT process is running and actively trying to establish a connection to the remote physical connection. The CMT process requires state transition with different signals being transmitted and received before moving on to the next state. The ten bits of CMT information are transmitted and received in the Signal State. Each state displays the number of times it was entered. In the above example, the Next State (Nxt) was entered 11 times.
The CFM state is wrap A in the sample output because the Cisco network server has not completed CMT with its neighbor to connect to Physical B.
The display (or nondisplay) of the Cisco upstream and downstream neighbor does not affect the ability to route data. The determination of the upstream and downstream neighbors is dependent upon all stations on the ring running the same version of Station Management (SMT). Since the Cisco upstream neighbor is also its downstream neighbor in the sample supplied previously, there are only two stations in the ring, the Cisco network server and the router at address 0800.2008.C52E.
Use the following EXEC commands to monitor the state of the FDDI interface. (Note that each command has a corresponding undebug command that turns off the messages displayed by these commands.)
debug fddi-smt-packets debug fddi-cmt-eventsThe debug fddi-smt-packets command enables logging of FDDI station management (SMT) packets, whereas the debug fddi-cmt-events command enables logging of FDDI Connection Management (CMT) transactions. See the X3T9.5 specification for more information about these packets and transactions.
Using special FDDI interface subcommands, you can set the token rotation time, set the transmission valid timer, control the transmission time, set the bit control, and start and stopping FDDI. This section also describes FDDI dual homing--a built-in configuration
capability of the Cisco FDDI software.
Use the fddi token-rotation-time interface subcommand to control ring scheduling during normal operation, and to detect and recover from serious ring error situations.
fddi token-rotation-time microsecondsThe argument microseconds determines the token rotation time (TRT). The default value is 5000 microseconds. The FDDI standard restricts the allowed time to be greater than 4000 microseconds and less than 165000 microseconds.
As defined in the X3T9.5 specification, the value remaining in the TRT is loaded into the token holding timer (THT). Combining the values of these two timers provides the means to determine the amount of bandwidth available for subsequent transmissions.
These commands set the rotation time to 24000 microseconds.
interface fddi 0 fddi token-rotation-time 24000
Use the fddi valid-transmission-time interface subcommand to recover from a transient ring error.
fddi valid-transmission-time microsecondsThe argument microseconds sets the transmission valid timer (TVX) interval. The default valid transmission timer value is 2500 microseconds.
These commands change the transmission timer interval to 3000 microseconds.
interface fddi 0 fddi valid-transmission-time 3000
Use the fddi tl-min-time interface subcommand to control the FDDI TL_MIN time (the minimum time to transmit a Physical Sublayer, or PHY line state before advancing to the next Physical Connection Management, or PCM state, as defined by the X3T9.5 specification).
fddi tl-min-time microsecondsThe specification defines the argument microseconds to be a value of 30. This value is used during the Connection Management (CMT) phase to ensure that signals are maintained for at least the value of TL_MIN so the remote station can acquire the signal.
These commands change the TL_MIN time from 30 microseconds to 100 microseconds.
interface fddi 0 fddi tl-min-time 100
Use the fddi cmt-signal-bits interface subcommand to control the information transmitted during the CMT signaling phase.
fddi cmt-signal-bits signal-bits phy-a|phy-bThe argument signal-bits is written as a hexadecimal number preceded by "0x"; for example, "0x208." The keywords phy-a and phy-b select the Physical Sublayer (Physical A or Physical B station), for control of each fiber.
The FDDI standard defines nine bits of signaling information (signal-bits) that must be transmitted:
| bit 2 | bit 1 | Physical Type |
|---|---|---|
| 0 | 0 | Physical A |
| 1 | 0 | Physical B |
| 0 | 1 | Physical S |
| 1 | 1 | Physical M |
Bits 1 and 2 are transmitted (signaled), and each physical type determines if it is allowed to connect to a type at the other end.
| bit 5 | bit 4 | Test Duration |
|---|---|---|
| 0 | 0 | Short test (default 50 milliseconds) |
| 1 | 0 | Medium test (default 500 milliseconds) |
| 0 | 1 | Long test (default 5 seconds) |
| 1 | 1 | Extended test (default 50 seconds) |
The default signal bits for the phy-a and phy-b keywords are as follows:
If the phy-a or phy-b keyword is not specified, then the signal bits apply to both physical connections.
In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned off using the shutdown interface subcommand described in the section "Shutting Down and Restarting an Interface," earlier in this chapter. The privileged EXEC commands cmt connect and cmt disconnect allow the operator to start and stop the processes that perform the Connection Management (CMT) function, and particularly, allows the ring on one fiber to be stopped.
The EXEC commands cmt connect and cmt disconnect are not needed in the normal operation of FDDI; these commands are mainly used in interoperability tests, and are entered at the EXEC prompt:
cmt connect [interface-name [phy-a|phy-b]]The optional argument interface specifies the particular FDDI interface. The optional keywords phy-a and phy-b specify a Physical Sublayer (A or B).
The following commands demonstrate use of the cmt connect commands for starting the CMT processes on the FDDI ring.
This command starts all FDDI interfaces:
cmt connect
This command starts both fibers on the FDDI interface unit 0 (zero):
cmt connect fddi 0
This command starts only Physical Sublayer A on the FDDI interface unit 0 (zero):
cmt connect fddi 0 phy-a
The following commands demonstrates using the cmt disconnect command for stopping the CMT processes on the FDDI ring.
This command stops all FDDI interfaces:
cmt disconnect
This command stops FDDI interfaces unit 0:
cmt disconnect fddi 0
This command stops only Physical Sublayer A on the FDDI interface unit 0 (zero). This command causes the FDDI media to go into a wrapped state, so that the ring will be broken.
cmt disconnect fddi 0 phy-a
Configuration of the FDDI interface is not required for dual homing. The FDDI interface recognizes that it is attached to two M ports on the concentrators, and automatically supports dual homing.
Although most configuration for FDDI interfaces involves specific interface settings, a Cisco router's ability to buffer FDDI Station Management (SMT) messages is controlled globally. The following brief description outlines how you can control the buffering of SMT messages that are queued for processing.
Use the global configuration command smt-queue-threshold to set the maximum number of unprocessed Station Management (SMT) frames that will be held for processing. The command syntax is:
smt-queue-threshold numberThe argument number specifies the number of buffers used to store unprocessed SMT message that are to be queued for processing. Acceptable values are positive integers.
The default value for number is equal to the number of FDDI interfaces installed in the router.
This command helps ensure that Cisco routers keep track of FDDI upstream and downstream neighbors, particularly when a router includes more that one FDDI interface.
In FDDI, upstream and downstream neighbors are determined by transmitting and receiving SMT Neighbor Information Frames (NIFs).
The router can appear to lose track of neighbors when it receives an SMT frame and the queue currently contains an unprocessed frame. This occurs because the router discards incoming SMT frames if the queue is full. Discarding SMT NIF frames can cause the router to lose its upstream or downstream neighbor.
The command no smt-queue-threshold restores the queue to the default.
The following example specifies that the SMT queue can hold ten messages. As SMT frames are processed by the system, the queue is decremented by one.
smt-queue-threshold 10
The Cisco High-Speed Serial Interface (HSSI) consists of two cards:
The card provides a single full duplex synchronous serial interface capable of transmitting and receiving data at up to 52 megabits per second. The HSSI is a de facto industry standard providing connectivity to T3 (DS-3), E3, SMDS (at a DS-3 route), and other high-speed wide-area services through a DSU or Line Termination Unit.
The high-speed, full duplex synchronous serial interface is supported only on Cisco's modular network server products.
To specify the HSSI, use this configuration command:
interface hssi unitSpecify the interface connector number with the argument unit.
Follow this command with the routing or bridging interface subcommands for your particular protocol or application as described in later in this manual.
The cBus cards can query the appliques to determine their types. However, they do so only at system start-up, so the appliques must be attached when the system is started. Issue a show controllers cbus command to determine how the HSSI card has identified them. The command will also show the capabilities of the card and report controller-related failures.
This command begins configuration on interface HSSI 0.
interface hssi 0
The HSSI supports the serial encapsulation methods described in the section "Serial Encapsulation Methods," earlier in this chapter.
Use the command clear interface to reset the hardware logic on an interface. Enter this command at the EXEC prompt:
clear interface interface-nameThe arguments type and unit specify a particular interface type and its unit number. In this case, the argument type is hssi.
Use the command show interfaces to display information about the HSSI interface. Enter this command at the EXEC prompt:
show interfaces [type unit]Where type is the keyword hssi and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command for Cisco's HSSI is provided below. Table 1-9 describes the fields seen.
HSSI 0 is up, line protocol is up
Hardware is cBus HSSI
Internet address is 150.136.67.190, subnet mask is 255.255.255.0
MTU 4470 bytes, BW 45045 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 0:00:03, output 0:00:00, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants
0 parity, 0 rx disabled
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
17 packets output, 994 bytes, 0 underruns
0 output errors, 0 applique, 4 interface resets, 0 restarts
2 carrier transitions
| Field | Description |
|---|---|
| HSSI is {up |down} ...is administratively down | Tells whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. |
| line protocol is {up | down | administratively down} | Tells whether the software processes that handle the line protocol thinks the line is usable (are keepalives successful? |
| Hardware | Specifies the hardware type. |
| Internet address | Lists the Internet address followed by subnet mask. |
| MTU | Maximum Transmission Unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. |
| Encapsulation | Encapsulation method assigned to interface. |
| loopback | Tells whether loopback is set, and type of loopback test. |
| keepalive | Tells whether keepalives are set or not. |
| Last input | The number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| output hang | The number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
| Last clearing | The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared. |
| Output queue, Input Queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
| Five minute input rate, Five minute output rate | The average number of bits and packets transmitted per second in the last five minutes. |
| packets input | The total number of error-free packets received by the system. |
| broadcasts | The total number of broadcast or multicast packets received by the interface. |
| runts | The number of packets that are discarded because they are smaller than the medium's minimum packet size. |
| giants | The number of packets that are discarded because they exceed the medium's maximum packet size. |
| parity | Report of the parity errors on the HSSI. |
| rx disabled | Indicates inability to get a buffer when accessing a packet. |
| CRC | The Cyclic Redundancy Checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link. CRC errors are also reported when a far-end abort occurs, and when the idle flag pattern is corrupted. This makes it possible to get CRC errors even when there is no data traffic. |
| frame | The number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems. |
| overrun | The number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased. |
| packets output | Total number of messages transmitted by the system. |
| bytes output | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never happen (be reported) on some interfaces. |
| congestion drop | The number of messages discarded because the output queue on an interface grew too long. This can happen on a slow, congested serial link. |
| output errors | The sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
| applique | Indicates an unrecoverable error has occurred on the HSA applique. The system then invokes an interface reset. |
| interface resets | The number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down. |
| restarts | The number of times the controller was restarted because of errors. |
| carrier transitions | The number of times the carrier detect signal of a serial interface has changed state. Indicates modem or line problems if the carrier detect line is changing state often. |
Use the command debug serial-interface to debug HSSI events. Enter this command at the EXEC prompt:
debug serial-interfaceEnter the undebug serial-interface to turn off messaging.
The UltraNet Interface consists of two cards: the CSC-HSCI, which is a cBus resident card, and the CSC-ULA, which is a back-panel applique. The UltraNet Interface provides connectivity to the UltraNet product offered by Ultra Network Technologies.
To specify an UltraNet interface, use this configuration command:
interface ultranet unitSpecify the UltraNet interface connector number with the argument unit.
Follow this command with the appropriate routing or bridging interface subcommands for your particular protocol or application as described in later in this manual.
This command begins configuration on UltraNet interface 0:
interface ultranet 0
The UltraNet interface supports the UltraNet encapsulation only. Therefore, there is no encapsulation command for the interface. It will default to UltraNet encapsulation.
Use the command clear interface to reset the hardware logic on an interface. Enter this command at the EXEC prompt:
clear interface interface-nameThe arguments type and unit specify a particular interface type and its unit number. In this case, the argument type is ultranet.
Use the command show interfaces to display information about the serial interface and the state of source bridging. Enter this command at the EXEC prompt:
show interfaces [type unit]The argument type is the keyword ultranet and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command for Cisco's synchronous serial interfaces is provided below. Table 1-10 describes the fields seen.
UltraNet 0 is up, line protocol is up
Hardware is cBus UltraNet, address is 8/32
Internet address is 150.136.68.190, subnet mask is 255.255.255.0
MTU 3500 bytes, BW 125000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ULTRANET, loopback not set, keepalive set (10 sec)
ARP type: ULTRA
Last input 0:00:09, output 0:00:09, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 0 bits/sec, 0 packets/sec
6 packets input, 236 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants
0 parity, 0 rx disabled
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
6 packets output, 236 bytes, 0 underruns
0 output errors, 0 applique, 1 interface resets, 0 restarts
| Field | Description |
|---|---|
| UltraNet is {up |down} ...is administratively down | Tells whether the interface is currently active and if it has been taken down by an administrator. |
| line protocol is {up | down | administratively down} | Tells whether the processes that handle the line protocol are active. |
| Hardware | Specifies the hardware type. |
| Internet Address | Specifies the Internet address, followed by subnet mask. |
| MTU | Maximum Transmission Unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. |
| Encapsulation | Encapsulation method assigned to interface. |
| loopback | Tells whether loopback is set or not. |
| keepalive | Tells whether keepalives are set or not. |
| Last input | The number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| output hang | The number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
| Output queue, Input Queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
| Five minute input rate, Five minute output rate | The average number of bits and packets transmitted per second in the last five minutes. |
| packets input | The total number of error-free packets received by the system. |
| broadcasts | The total number of broadcast or multicast packets received by the interface. |
| runts | The number of packets which are discarded because they are smaller than the medium's minimum packet size. |
| giants | The number of packets which are discarded because they exceed the medium's maximum packet size. |
| parity | Report of the parity errors on the UltraNet interface. |
| rx disabled | Indicates inability to get a buffer when accessing a packet. |
| CRC | The Cyclic Redundancy Checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link. |
| frame | The number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems. |
| overrun | The number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased. |
| abort | An illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment. |
| packets output | Total number of messages transmitted by the system. |
| bytes output | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the transmitter has been running faster than the router can handle. This may never happen (be reported) on some interfaces. |
| output errors | The sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
| applique | Indicates an unrecoverable error has occurred on the ULA applique. |
| interface resets | The number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds time. This can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down. |
| restarts | The number of times the controller was restarted because of errors. |
Sometimes it is necessary to statically assign the UltraNet MAC layer address to the interface. This mechanism is needed if dynamic address assignment is not implemented on the Ultra Network Technologies interface on the network. Use the ultranet address interface subcommand to assign the MAC layer address of the interface:
ultranet address ultranet-mac-addressThe argument ultranet-mac-address is the MAC address of the UltraNet service line.
These commands assign address 8/32 to the UltraNet interface.
interface ultranet 0 ultranet address 8/32
The dial backup service provides protection against WAN down time by allowing you to configure a backup serial line via a circuit-switched connection.
To configure dial backup, associate a secondary serial interface as a backup to a primary serial interface. This feature requires that an external modem, CSU/DSU device, or ISDN terminal adapter (TA) attached to a circuit-switched service be connected on the secondary serial interface. The external device must be capable of responding to a DTR signal (DTR active) by auto-dialing a connection to a preconfigured remote site.
The dial backup software keeps the secondary line inactive (DTR inactive) until one of the following conditions is met:
These conditions are defined using the interface subcommands described later in this section.
When the software detects either a lost Carrier Detect signal from the primary line device, or that the line protocol is down, the software activates DTR on the secondary line. At that time, the modem, CSU/DSU, or ISDN Terminal Adapter (TA) must be set to dial the remote site. When that connection is made, the routing protocol defined for the serial line will continue the job of transmitt